18970381 has 4 divisors (see below), whose sum is σ = 19483132. Its totient is φ = 18457632.

The previous prime is 18970361. The next prime is 18970411. The reversal of 18970381 is 18307981.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17147881 + 1822500 = 4141^2 + 1350^2 .

It is a cyclic number.

It is not a de Polignac number, because 18970381 - 2⁹ = 18969869 is a prime.

It is a super-2 number, since 2×18970381² = 719750710570322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 512713 = 18970381 / (1 + 8 + 9 + 7 + 0 + 3 + 8 + 1).

It is the 4356-th Hogben number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18970381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18970361) by changing a digit.

It is a nontrivial repunit in base 4355.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256320 + ... + 256393.

It is an arithmetic number, because the mean of its divisors is an integer number (4870783).

Almost surely, 2^18970381 is an apocalyptic number.

It is an amenable number.

18970381 is a deficient number, since it is larger than the sum of its proper divisors (512751).

18970381 is an equidigital number, since it uses as much as digits as its factorization.

18970381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 512750.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 18970381 is about 4355.5000860980. The cubic root of 18970381 is about 266.7014341822.

The spelling of 18970381 in words is "eighteen million, nine hundred seventy thousand, three hundred eighty-one".